a tip led cops in california to an explosive find. look at this. [siren] >> police say somebody reported the guy was building bombs in his house so they evacuated the neighborhood just north of oakland bomb squad took the place. >> cops took the man who lived there into custody. listen to one of his neighbor creep on the block. he would be making all kinds of noise at all times of night, you know. it would be so loud, shake my house. >> shepard: investigators are trying to figure out why the guy was making these explosives in the first place. another huge blast blew an entire house apart in denver. this time they tell us it was an accident. people in the neighborhood reported they smelled gas and then all of a sudden the explosion leveled a home and damaged two others. just look at the pink foam here. can you see that? those are bits of insulation which witnesses say fell throughout the entire neighborhood like snow. a woman and her four kids went to the hospital. they are said to be doing okay now. crews are still searching for a man who is still